Caption: Animation of an experiment used to measure the effect of temperature on the rate of a chemical reaction. This reaction is at 50 degrees Celsius. It starts with a colourless transparent mixture of sodium thiosulfate (S2O32-) and hydrochloric acid. The acid attacks the thiosulfate, splitting it into sulfur dioxide gas and solid sulfur, which forms particles that gradually make the solution more opaque. The rate of the production of the sulfur depends on the temperature: it is faster when the the temperature is higher. This is because the reactants are moving more quickly, leading to more collisions, and more of the collisions are between reactants that have the energy required to break the chemical bonds.